Carb Cooling Fan Relay Question (with video) (2 Viewers)

[60series777]

Hi guys, wondering if you can help me identify what this noise is that I am hearing when I shut off my 1985 fj60. I recently had a brake job done and after driving home I noticed the carb cooling fan is working for the first time under my ownership. Only thing is there is a pretty noticeable “clicking” type noise under the drivers side dash when I turn the engine off. I tried to capture it in the short video below. Does this sound like a worn out/faulty relay to you? I probably need to dig into my owners manual and check all connections but figured I would ask you all first. Thank you in advance for any insight.

 

[MostlyNuts]

Sure sounds like the fan relay going nuts. Run it again and try disconnecting the therm resistor/temp sensor and see if it stops the clicking. Was the fan never working before this? Maybe remove the relay and clean the contacts also, for good measure.

 

[60series777]

Sure sounds like the fan relay going nuts. Run it again and try disconnecting the therm resistor/temp sensor and see if it stops the clicking. Was the fan never working before this? Maybe remove the relay and clean the contacts also, for good measure.

The fan was never working, in fact I didn’t know there was a carb fan. I’m guessing my mechanic either jostled something or reconnected it while working through the brakes. It seems like a “nice to have” item so I’d like to salvage it.

I checked my haynes manual but I didn’t find a diagram for the carb fan. Is the relay one of those metallic can looking ones or is it a box shape? And the temp sensor, what does that look like?

 

[MostlyNuts]

For 1988-1990, at the bottom of page 12-39 in the Haynes 92056 1980-1996, FJ60, 62, 80, FZJ80 book, you will find the diagram for the cooling fan circuit. For 1980-1987 it's on page 12-22.
I'll try and get some pics and post 'em.

 

[60series777]

Ok thanks a lot I’ll check that. Just got the little one down for a nap, going to mess with it now.

 

[60series777]

So I started by looking at the diagram in the haynes manual but I still didn’t understand what the relay looked like. Here’s a picture for future reference in case anyone comes across this thread with a common issue:

For my smooth brain, it was easier to follow wires from the fan, and sure enough there was a severed wire. The mechanic likely jostled the wire harness around just right so that it was rubbing up against some sort of ground and intermittently making the cooling fan work (bad contact also explains the clicking type noise in the video above).

I think this is the wire that is intended to go to the manifold temp sensor, but I read a few other threads on here that suggested it is fine to just ground the wire as the fan has an automatic cutoff ~20 to 30 minutes after turning off the vehicle. I opted to do that instead and the fan started blowing nicely, however there was still some crackling noise near the vent on the front fender. I pulled that off and cleaned the chute which had some electrical tape flapping around in it:

30 minutes later on the dot my fan shut off. Excited to see if this helps my hot starts, which always seem to take a little bit of extra effort.

 

[Rustyj41]

I have an extra fan and relay for sale if you need one.

 

[MostlyNuts]

Very nicely done! Fan control and sensor pic here.

 

[60series777]

Very nicely done! Fan control and sensor pic here.

View attachment 3538506
View attachment 3538505

Thank you! I’ll have to see if I have a working temp sensor, maybe I’ll go back and do it the “right” way at some point. For now I am stoked just to have it working.

 

[open country]

Count me as one of the club who grounded their carb fan and are satisfied with the solution.

 

[60series777]

Count me as one of the club who grounded their carb fan and are satisfied with the solution.

Seems like many of us have gone this route. One less 39 year old electrical component to depend on.

 

[MostlyNuts]

Fair enough. I was thinking also of recreating the functions with an arduino nano and 12v relay to simulate. Then, stuff it all in the OEM housing with the standard connector for a plug and play option.
If I ever get around to it I'll post it here.
Cheers!